RMAN automatically performs autolocation of all files that it must back up or restore. If you use the noncluster file system local archiving scheme, then a node can only read the archived redo logs that were generated by an instance on that node. RMAN never attempts to back up archived redo logs on a channel it cannot read.
During a restore operation, RMAN automatically performs the autolocation of backups. A channel connected to a specific node only attempts to restore files that were backed up to the node. For example, assume that log sequence 1001 is backed up to the drive attached to node1, while log 1002 is backed up to the drive attached to node2. If you then allocate channels that connect to each node, then the channel connected to node1 can restore log 1001 (but not 1002), and the channel connected to node2 can restore log 1002 (but not 1001).